Mine roof bolt having wedge sections mounted on a t-headed shank



March 1953 c. P. MOCABE ETAL 2,825,258

MINE ROOF BOLT HAVING WEDGE SECTIONS MOUNTED ON A T-HEADED SHANK FiledJuly 23, 1954 2 Sheets-Sheet 1 V I a 61! n /A 4.6

I I ll 4 Arro /m5) c. P. MOCABE ET AL 2,825,258 BOLT HAVING WEDGE s nousMOUNTED March 4, 1958 MINE ROOF Filed July 23. 1954 ON A T-HEADED SHANK2 Sheets-Sheet 2 United States Patent MINE, ROOF BOLT T HAVING; WEDGE:.ESECTIONS MOUNTED ONAuTHEADED SHANK':

Charles P. McCabe, Bay Village, and OdinWerther, East Cleveland, Ohio,assignors to Republic Steel Corporation, Cleveland, Ohio, a corporationof-Ne'w Jersey Application .July 23, 1954,.= Serial-No.. 445,262 7 3Claims. (Cl; 85*2.4) t

Thisinvention relates to the construction of wedge head bolts, andparticularly to bolts of a typeadapted for use asmine roof bolts.v v

There is disclosed in ;the copending application of Charles P. McCabe,Serial No. 358,'4l4, file'd.'iMay 29, 1953, now Patent No. 2,787,931,issued'April 9;"1957;

mains behind, and then cooperates with'th'e wedging surfaces on thewedge head to anchor the bolt firmly in the hole.

Bolt heads are commonly formed integrally with the shank of the bolt bya forging operation on the end of the piece of bar stock from which thebolt is made. The bolt head is formed during the forging operation by aflow of bar stock material. This type of forging operation to form abolt head has limitations as. to the size of the head which can besuccessfully formed on bar stock of a given diameter.

A wedge head bolt of the type described in the McCabe applicationmentioned above requires a large amount of material. For that reason, ithas been found that such a bolt head is difficult to make as a singleforging.

An object of the present invention is to provide an improved wedge headbolt structure of the type described.

A further object of the invention is to provide an improved method ofconstructing such a wedge head bolt by making it in separate parts andassembling them.

Another object is to provide an improved bolt of the type describedcapable of withstanding substantial stresses between the bolt head andthe shank.

Another object is to provide a method of forming a bolt head of the typedescribed which is economical and rapid and adaptable to massproduction.

The foregoing and other objects of the invention are attained in themethod and apparatus described herein by forming a bolt with a simpleT-head of relatively small dimensions. On the arms of this T-head aremounted two complementary wedge sections. Each wedge section consists ofa wedge-shaped. body having a central aperture to receive one arm of theT-head and a recess along its inner side to receive one side of theshank of the bolt. After the wedge sections are assembled on the T-head,the ends of the T, which project through the apertures in the wedgesections, are flared to grip the wedge sections tightly and hold them onthe Thead.

Other objects and advantages of the invention will become apparent froma consideration of the accompanying specification, claims and drawings.

In the drawings:

Fig. 1 is an elevational view of a complete mine root boltassemblyincluding a wedge head bolt. constructed in accordance with theinvention, with certain parts broken away and shown in section toillustrate details of the as- Fig. 2 is an elevational view of acomplete wedge head bolt assembly embodying the invention;

Fig. 3 is a plan view of the. bolt of Fig.2;

Fig.4 is a right-hand elevational view of the boltjof Fig. 2, certainparts being shown in section;

Fig. 5 isan elevational view of a T-head bolt which comprises anessential partof thewedge headbolt assembly of Fig. 2; r

Fig. 6 is a plan view of the T-head bolt of Fig. 5;

Fig. 7 is aright-handelevational view of the T-h'ead bolt. of Fig. 5;

Fig. 8'is an elevational view of one of the wedge sections inthe wedgehead bolt' assembly of Fig. 2;

Fig. 9 is a plan view. of. the wedge head section of Fig. 8;

Fig. 10 is a sectional 'view on theline .XX of the wedge section of Fig.8;and

Fig. 11 is a cross-sectional view taken on the line XIXI of Fig. 8,looking in the direction of the arrows Referring to. thedrawings, thereis shown in Fig. 1, a

complete mine roof bolt'including a bolt 1 having a Wedge head 2 and apair of anchor shell sections 3 supported on;

the wedge head. The shell sections 3 are provided on their upper endswith bent-over tangs 3a which are .re-,

ceived in a central recess 2a formed in the wedge-head 2.

The tangs 3a are of spring material and bias the skirts of the shellsections 3 outwardly. The arrangement is such that when the bolt withthe shell sections mounted on it is inserted into a hole, the shellsections are pressed back against the bolt by the sides of the hole, sothat the shell sections move into the hole with the bolt. When the headof the bolt has been inserted to the desired depth, it is then pulledoutwardly slightly, and the inclined surfaces 2b of the wedge head 2cooperate with wed-ging surfaces 311 formed on the shell sections 3 toforce the latter tightly against the sides or wall of the hole, therebyanchoring the bolt firmly in the hole.

Referring now to Figs. 2 to 11, it may be seen that the wedge head boltgenerally indicated by the reference numeral 1 is built up from a T-headbolt 4 and two wedge sections 5. The T-head bolt 4 comprises a shank 4aand two oppositely projecting arms 412. Each wedge section 5 consists ofa generally wedge-shaped body having a central aperture 5a adapted toreceive one of the arms 4b of the T-head, and a longitudinally extendingrecess 5b, which is adapted to receive and engage tightly the shank 4a.

The arms 41) of the T-head are tapered outwardly, i. e., their diameteris greater at the shank than at the free endt'he purpose being toprovide greater shear strength at the shank and to facilitate formingthe head. The apertures 5a in the wedge section 5 are similarly taperedso that the wedge sections fit snugly on the T-head. After the Wedgesections are mounted on the T-head, the ends of the T may be flared bystriking them sharply with a convex surfaced tool, thereby spreadingtheir edges so that they grip the wedge sections 5 tightly and hold themin place.

The wedge sections 5 are provided with fiat abutting surfaces 50. Whenboth wedge sections are in place on the T-head bolt 4, the surfaces 5cabut against each other and are held in firm engagement when the ends ofthe T-head arms 4b are flared.

The recesses 5b conform in contour to one-half the shank 4a. In thestructure shown, the shank 4a is cylinclrical and the recesses 5b aresemi-cylindrical.

.The recesses 5b extend throughout the length of the wedgesections 5, asshown in Figs. 8 and 10. The upper Patented Mar. 4, 1958 ends of theserecesses 5b are above the upper end of the T-head bolt 4, and cooperateto define a cylindrical recess 2a in the upper end of the wedge headbolt. The cylindrical recess 2a is adapted to receive the tangs 3asupporting the shell sections 3, as illustrated in Fig. 1.

Each of the principal parts of the wedge head boltdescribed herein maybe formed readily and accurately by a simple forging operation.Thisstructure is economical of material and may be assembled rapidly.When assenr bled, the parts remain permanently in place, even thoughsevere stresses may be applied to the wedging surfaces.

While we have shown and described a preferred embodiment of ourinvention, other modifications thereof will readily occur to thoseskilled in the art, and we therefore intend our invention to be limitedonly by the appended claims.

We claim: i

1. A wedge head mine roof bolt construction comprising a shank having atone end two oppositely projecting arms defining a T-head, and twocomplementary wedge sections, each wedge section comprising a bodyhaving an aperture receiving one of said T-arms, a recess to receive oneside of said shank, said recess intersecting said aperture, and twoinclined wedging surfaces extending longitudinally of the section andparallel to the axis of said aperture and converging toward a pointspaced along the shank from said T-arms, said wedge section bodieshaving abutting surfaces, said arms being flared at their ends afterassembly of the wedge sections thereon to hold the wedge sections inplace, said recesses extending beyond said T-head and providing agenerally cylindrical aperture in the end of the wedge head.

2. A wedge head mine roof bolt construction comprising a shank having atone end two oppositely projecting arms defining a T-head, and twocomplementary wedge sections, each wedge section comprising a bodyhaving an aperture receiving one of said T-arms, a plane surfaceextending at an angle to the axis of said aperture and adapted to abut asimilar surface on the other wedge section, and two inclined planesurfaces extending longitudinally of the section and parallel to theaxis of said aperture and converging toward a point spaced along theshank from said T-arms.

3. A wedge section adapted for mounting on a T-head mine roof boltincluding a body having an aperture adapted to receive one of the T-armsof said T-head mine roof bolt and a recess adapted to receive the shankof the belt, a plane surface extending at an angle to the axis of saidaperture and adapted to abut a similar surface of a complementary wedgesection similarly adapted for mounting on said T-head mine roof bolt,and two inclined plane surfaces extending longitudinally of the sectionand parallel to the axis of said aperture and converging toward a pointspaced along the shank-receiving recess from said T-arms.

References Cited in the file of this patent UNITED STATES PATENTS 13,177Loudon et al July 3, 1855 347,921 Connolly Aug. 24, 1886 448,224 GloverMar. 17, 1891 680,609 Marquardt Aug. 13, 190i 1,699,546 Scheibli Jan.22, 1929 1,851,292 Rasmussen Mar. 29, 1932

